DEVOPS-419 WIP: Migrate narrative-traefiker to using classes instead of modules for orchestration handlers

[sychan]

This is a WIP feature branch that replaces the original Python module based method of "pluggable" orchestration support with a class based model. It is a work in progress and needs some additional work:

• Add a base class that has the signature/interface that needs to be implemented
• Fully migrate the app.py code so that it just uses an instance variable for the orchestration object, instead of a bunch of method pointers
• Test the code in Next to ensure that it all still works as before
• Add some basic tests (somewhat problematic since it requires a running Rancher instance and traefik, though it could be done)

[lgtm-com]

This pull request fixes 13 alerts when merging 7c0b979 into a4e1243 - view on LGTM.com

fixed alerts:

• 13 for Clear-text logging of sensitive information